In recent years there has been renewed interest in harnessing an ancient energy - the wind.The propeller aeroturbine has attained the highest degree of development. However, because the methods for analytically predicting the characteristics of a Savonius windmill are not available, it has not been possible to carry out a detailed design of this type of windmill power system.This paper discusses the performance characteristics of a Savonius wind turbine power system with a d.c.generator.The theoretical results agreecomparatively well with the experimental results.The effects of changes in wind speed and loadresistance on the performance are discussed.